1. Field of the Invention
The present invention relates to a color filter, a method for producing the same, a display apparatus, and an electronic device therewith.
This application claims priority on Japanese Patent Applications Nos. 2002-339297 and 2003-300144, the contents of which are incorporated herein by reference.
2. Description of Related Art
In recent years, liquid crystal apparatuses have been widely used as means for displaying information in electronic device such as laptop computers, cellular phones, and electronic notebooks. For such liquid crystal apparatuses, semi-transmitting and reflecting liquid apparatuses having advantages of both transmission liquid apparatuses providing display utilizing light from a built-in light source, and reflection providing display utilizing external light such as sunlight are known. The semi-transmitting and reflecting liquid apparatus enables the display to be viewed even in a dark environment, and also enables the display to be provided utilizing external light in bright environment, thus making it possible to reduce power consumption compared to the transmission liquid crystal apparatus in which a light source is lit all the time.
The semi-transmitting and reflecting liquid crystal apparatus is generally configured such that a semi-transmitting and reflecting layer is provided on the surface on the liquid crystal layer side of a substrate located on the side opposite to the visual viewing side, of a pair of substrates facing each other with a liquid crystal layer held therebetween. The semi-transmitting and reflecting layer is constituted by, for example, a reflection layer having an aperture having a slit-shape for each dot and in the semi-transmitting and reflecting layer having such a configuration, apertures serve as light transmission portions and other portions serve as light reflection portions. In addition, semi-transmitting and reflecting liquid crystal apparatuses having a color filter on one substrate to enable color display is also known. Hereinafter, a substrate having a color filter is referred to as a “color filter substrate”.
Methods for producing the color filter substrate are classified into several types according to materials of colored portions and production processes, and an inkjet method of discharging a coloring ink from a discharge nozzle of an inkjet head to form a large number of colored portions on a substrate has been recently proposed.
FIG. 34 shows a color filter substrate produced by the inkjet method. This color filter substrate has on a substrate 900 black matrixes (blackout layers) 901, reflection layers 902 made of metal such as Al, bank portions 903, a colored portion 905R, a colored portion 905G of G (green), a colored portion 905B of B (blue), and an overcoat layer 908. Colored portions 905 are formed by discharging coloring inks as colored portion constituting materials by an inkjet head (not shown) and drying the coloring inks.
In addition, a light source is provided on the substrate 900 side, and this light source is lit, whereby source light 910 passes to the viewer's side through the substrate 900, colored portions 905 and an overcoat layer 908 to provide so-called display in transmission mode. In addition, external light 920 such as sunlight on the viewer's side passes through the overcoat layer 908 and colored portions 905, is reflected by the reflection layer 902, and further passes to the viewer's side through colored portions 905 and the overcoat layer 908 to provide so-called “display-in-reflection mode”.
In the color filter substrate shown in FIG. 34, source light 910 passes through colored portions 905 only once, and is then emitted to the viewer's side when display is provided in transmission mode, while external light 920 passes through the color filter substrate twice, i.e., before and after it is reflected by the reflection layer 902, and is then emitted to the viewer's side. Thus, a problem arises in that the color of external light 920 passing through colored portions 905 becomes deeper than the color of sunlight 910, resulting in a dark display color, that is, display of colors of the same density cannot be obtained in transmitting and reflecting modes.
In addition, the conventional method for producing a color filter has a problem in that exposure processing and etching processing are each required to be carried out at least twice for forming the black matrix 901 and the bank portion 903, and thus the production process is likely to be complicated.